At the present time the automotive industry is one of the most rapidly developing branches of industry, so that engineers are constantly turning to non-traditional engine design in particular to piston engines with axially-arranged cylinders. The advantages of axial arrangement of cylinders in I.C. piston engines, resulting in their smaller weight and dimensions, are widely known. As compared with traditional piston engines incorporating a crank gear for converting the reciprocating motion of pistons into rotary motion of the crankshaft the size and weight of automotive axial-piston engines are reduced 1.5-2 times, and the aerodynamic resistance of the motor vehicle can be reduced due the smaller space occupied by the engine under the engine hood.
Modern requirements for reduction of the amount of cancerogenic substances exhausted by I.C. engines of transport facilities together with the exhaust gases and for diminishing the consumption of unreplenishable supplies of fuel force machine builders to turn to axial-piston engines with a variable cylinder volume.
Where such engines are used in vehicles under conditions of city traffic the fuel consumption is reduced by 30-40% with a proportional reduction of the amount of concerogenic substances in the total engine exhaust.
Thus, the axial-cylinder engine is the latest advancement in the development of I.C. piston engines.
However, up to the present time attempts to design a reliable efficient axial-piston engine have failed due to alternating fatigue stresses originating in the parts of the mechanism which converts the reciprocating motion of cylinder pistons into rotary motion of the shaft.
Attempts to solve the problem of ensuring reliable performance of the axial-piston engine resulted in the appearance of an axial-piston machine (FR Application [R/] 3420529 A.sub.1). The body of the known machine accommodates a cylinder block with cylindrical spaces whose axes are parallel with the longitudinal axis of the shaft. Pistons reciprocate in those spaces, each piston articulated to one end of a rod whose other end is articulated to a swash plate. The articulated joint of the other end of the rod to the swash plate is formed by means of a first cylindrical pin passing through the lugs of the yoke constituted by the other end of the rod and through an intermediate member, and a second cylindrical pin whose axis is perpendicular to the axis of the first pin, passing through the intermediate member and the lugs in the swash plate. The swash plate is installed, via a support, on the inclined crank of the shaft which latter is located on supports in the engine body. The swash plate is connected by a universal joint with the body. The support of the swash plate on the inclined crank of the shaft is spherical which provides for swinging of the plate while the reciprocating motion of the pistons in converted into rotary motion of the shaft.
The universal joint yoke is located in the cylinder block with a provision for longitudinal motion, viz., along the longitudinal axis of the shaft. The movement of the yoke entails the movement of the spherical support over the inclined shaft journal and a reduction of the swash plate angle which brings about a reduction of the swept volume of engine cylinders.
The use of one universal joint fails to ensure uniform precession of the swash plate due to changes in its angular velocity which take place twice per crank-shaft revolution in a plane perpendicular to the longitudinal axis of the swash plate. This produces a strong moment of inertia of the mass of the swash plate and parts associated therewith, said moment resulting in rapid fatigue failure of the universal joint.
The use of the universal joint as one of the swash plate supports still further reduces its reliability due to the heavy alternating loads imposed by the swash plate on the joint.
The provision of one spherical support of the swash plate results in this case in that the reaction forces originating on the swash plate and transmitted from it to the body via the shaft and universal joint are destructive to the shaft due to strong bending moments applied to it and destructive to the universal joint due to alternating dynamic loads.
The universal joint in the known design of the axial-piston engine is rather large because it performs the function of one of the swash plate supports and this hinders the development of the spherical surface of the support resting on the inclined journal of the shaft. This support takes the strongest forces arising in the engine while converting the reciprocating motion of the pistons into rotary motion of the shaft and, in view of the limited dimensions of the spherical surface of the support, its serviceability is low due its limited durability.
Next, the inclination angle of the longitudinal axis of the swash plate to the longitudinal axis of the crankshaft is 40.degree.. This causes large amplitude angular oscillations of the swash plate relative to its axis, which produces heavy inertial loads resulting in engine failure.
It follows from the above that the known machine is one of the attempts to create an axial piston engine, and is unsuccessful because of the above-cited disadvantages.
An attempt to eliminate the angular oscillations of the swash plate relative to its longitudinal axis was materialized in an axial-piston machine taught by U.S. patent, A, U.S. Pat. No. 2,424,660. The body of this machine houses a cylinder block with spaces whose axes are parallel to the longitudinal axis of the shaft and which accommodate reciprocating pistons. Each piston is articulated with one end of a rod whose other end is articulated with the swash plate. The latter is installed via a support on the inclined journal of a shaft mounted on supports in the frame. The swash plate is connected by two universal joints with the body. The swash plate support is an angular ball bearing whose inner race is connected rigidly with the inclined shaft journal while the outer race is secured on the swash plate. This shows that there is only one support which carries all loads impossed by the swash plate. Such a single-support fastening of the swash plate on the inclined shaft journal keeps the swash plate from moving along the inclined journal and from changing its angle of inclination. Thus, it is not possible to develop a machine with a variable swept volume of its cylinders.
In spite of the fact that the above-mentioned function of the machine is not attained, the connection of the swash plate with the frame via two universal joints substantially improves the performance of the machine, since there are no angular oscillations of the swash plate along its longitudinal axis which, in turn, precludes the destructive inertial loads caused by such oscillations.
Each universal joint consists of a ring with four pins which are arranged in one plane and have mutually perpendicular axes. Two coaxial pins of one universal joint are articulated with the swash plate, while the other two pins of this joint are articulated with the intermediate member in the form of a ring. The latter is articulated with the coaxial pins of the other universal joint.
The mutually--perpendicular pins are articulated with the lugs of a hollow part secured in the engine body. Inasmuch as the known design has no fixed position of the bisector plane passing through the point of intersection of the longitudinal axes of .the shaft and the swash plate and dividing in half the angle formed by the planes, each of which passes through the mutually--perpendicular axes of the universal joint pins, the service life of the universal joints is reduced considerably because of the additional unbalanced loads arising therein.